1. Field of the Invention
The present invention relates to a microcontact printing device and a printing method thereof, especially to a roller microcontact printing device and a printing method thereof.
2. Descriptions of Related Art
In traditional manufacturing processes of organic thin films, the organic thin film is produced by various techniques such as thermal oxide growth in a furnace tube or chemical vapor phase deposition so as to deposit an organic thin film on a substrate. These are high temperature processes. This results in that the organic thin film is unable to be deposited on flexible substrate because primary flexible substrate candidates are plastics. The flexible substrate is not durable in high temperature environments and this limits fabrication of semiconductor components on the flexible substrate.
In order to solve above problems, the organic thin film can be printed on the substrate by transfer stamping. The printing methods available now include ink-jet printing, slot die coating, screen printing, letterpress printing, offset printing, gravure printing, and microcontact printing. Nowadays the manufacturing of semiconductor devices is down to micro- and nanometer-scale. Thus only microcontact printing in the above printing methods matches the requirement.
In a microcontact printing device, a layer of thin film material is deposited on a stamp. Then the stamp is brought into contact with a substrate and the thin film material is transferred to the substrate. However, the contact area of the stamp is unable to be adjusted. Once the surface area of the organic thin film is increased, a new stamp is prepared and this increases the cost. While transferring the thin film material to the substrate by the stamp, the feeding of the substrate needs to be stopped when the substrate is fed by a roll-to-roll conveyor. Thus it is impossible to carry out the automatic and continuous thin film production.
In order to solve above problems, there is a need to provide a roller microcontact printing device used in thin film production, especially in production of organic thin film. The organic thin film production is not necessary under high temperature conditions. There is no need to use chemical solution for etching. Thus the production cost is reduced effectively and the manufacturing is environmentally friendly.
Moreover, the roller microcontact printing device includes a transfer roller by which a thin film layer is transferred to the substrate. The transfer area of the transfer roller is determined by the number of laps the transfer roller rotates so that the transfer area is adjustable. This solves the problem of general stamp transfer printing with fixed transfer area. The roller microcontact printing device can be used and moved together with a roll-to-roll conveyor module an as to produce thin films continuously and automatically.
Normally, in order to transfer the patterns, roller type printing devices such as letterpress printing, offset printing, and gravure printing need back up pressure to act on the printing roller. That makes those printing devices have to be durable strength and structure. On contrast the roller microcontact printing based on the adhesion-work of the solutions, there is no need for the pressure force to transfer the patterns for this printing device, so the device would be able to have longer lifetime and more easy to maintain.